Screw-cutting die



(No Model.)

F.1N. GARDNER. SCREW CUTTING DIE.

No. 420,904. Patented Feb. 4, 1 90 a may,

UNITED STATES PATENT OFFICE.

FREDERICK N. GARDNER, OE BELOIT, \VISCONSIN.

SCREW-CUTTING DIE.

SPECIFICATION forming part of Letters Patent No. 420,904, dated February4, 1890.

Application filed October 22, 1888. Serial No. 288,826. (No model.) I

To all whom it may concern.-

Be it'known that I, FREDERICK N. GARD- NER, of Beloit, in the county ofRock and State of Wisconsin, have invented certain new and usefulImprovements in Screw-Outting Dies; and I do hereby declare that thefollowing is a full, clear, and exact description thereof, referencebeing had to the accompanying drawings, and to the letters of referencemarked thereon, which form a part of this specification.

This invention relates to adjustable screwcutting apparatus comprising adie-stock and removable or interchangeable dies.

The invention has for its object to provide what I have termed amicrometer adjustment of the dies, by which the latter may be speedilyand accurately adjusted while out of the stock, to give a predetermineddiameter of a screw to be out.

In Letters Patent of the United States No. 250,801, granted to meDecember 13, 1881, I have described a die-stock-provided with stops orabutments for the two-part dies in the ends of the die box or yoke,together with adjusting-screws in the dies, which bear against theabutments, by which the dies may be adj usted to give a screw-bolt ofthe desired diameter.

The object of the invention set forth in said Letters Patent was toprovide a construction by which a series of adjustable dies could befitted to one die-stock, and any of the twopart dies, after beingexactly adjusted, could be removed and replaced without deranging theadjustment, the die-stock being meanwhile used for other dies. In thatcase the same dies were not intended to be used for cutting more than asingle size of screw, since adjustment was a matter requiring so muchcare and time that, once adjusted, they were to be left undisturbed andother dies employed for even slight variations. It was also a difficultywith such former construction that a change or movement of the adjusting-screw, mischievously or otherwise made when the die was out ofthe stock, could not be detected, and there was not that certainty ofobtaining the proper diameter of the screw which has been founddesirable. Besides, if it were necessary or desired to cut a bolt ofslightly less or greater diameter than those for which the dies had lastpreviously been used and other dies for such purposes were not at handit was necessary to make the usual trials and to readj ust the dies bymeans of their adj Listing-screws both for the new size and to restorethem to their former size, all of which required their removalandreinsertion at each trial, and involved considerable trouble and lossof time, besides not giving at last that accuracy of result necessary inthe use of these tools. To remedy these defects, I have provided thedies with what may be termed a micrometer-scale, consisting of a mark ormarks adjacent to the adj usting-screw by which, in conjunction with amarked screw, the dies may be set before being placed in the stock togive any one of several possible diameters of screw.

Describing the invention by reference to the accompanying drawings,Figure 1 is a top View of a die-stock having a central yoke the ends ofwhich form abutments against which may bear the adjusting-screws in thedies, also there shown. Fig. 2 is a longitudinal section of one of thedies detached, showing an adjusting-screw therein. Fig. 3 is an end viewof one of the dies containing the adjusting-screw and also provided withmarks on the die and a mark on the screw by which the micrometeradjustment contemplated may be eifected in the manner described.

The die-stock, as here shown, contains additional improvements in thenature of a movable side support or V-shaped rib for holding the dies,which rib is movable sidewise in the stock or to and from the oppositesimilar die-support, whereby the dies may be conveniently removed andinserted. This feature of construction forms no part of the presentinvention, but is described and claimed in another application forpatent filed by me of even date herewith and serially numbered 288,825.

A is a die-stock, of which A is the yoke or die-box and A A are thehandles. The end stops of the yoke or die-box, against which the diesabut to prevent their spreading in operation, are shown at a a, being inthe present case in the form of central projections at the ends of theyoke A, so that they are adapted to be squared 01f conveniently to astandard distance apart.

B B are the dies, and B B are the adj usting-screws set in the outerends of the dies. These screws are preferably fiat-faced, so as to bearbroadly and squarely against the abutments a a, of the stock and tothereby hold the dies firmly and without yielding. The screw B isprovided with some sort of mark Z) upon its end, at or near itsperiphery, which mark is, desirably, not the usual slit for thescrew-driver by which the adjustingscrew is turned, but may be such slitwithout departure from the invention. After the dies B B are finishedthey are supplied with the adjusting-screws B B and placed in the stockfor the purpose of adjustment, and the screws are retracted from oradvanced into the dies until the latter give the standard or requireddiameter of thread on a bolt cut by said dies. The dies are then removedand a mark, as b, is carefully made in the end of each die opposite themark in the screw. The dies are then adjusted to cut a thread of acertain smaller or greater diameter, (within limits consistent withperfection of thread,) and one or more marks, as 11 are made in the endof the die to indicate these limits. The dies thus marked maybe used foreither of the sizes of screw-thread which it is adapted to out andimmediately reset or adjusted to another size without experiment forthat purpose and simplyby turning the screw to bring" the mark thereonin line with the appropriate mark on the die. By these means the nicestpossible adjustment and readjustment of the dies are conveniently andquickly made, while the utmost certainty of results as to size of screwproduced by the dies is assured in every case.

The dies will be furnished by the manufacturer with the micrometer-scaleapplied thereto and duly marked (as formerly) with their standard size,so that the user can make any adjustment desired and can restore the dieto its standard without delay or uncertainty.

I claim as my invention- A screw-cutting die for use in a stock havingfixed end stops, said die being provided with a screw-threaded hole inits outer end, with a marked-headed adj ustin -screw fitted to said holeand with a mark or marks on its end face outside the screw-head, wherebya desired adjustment may be assured to the die before placing it in itsstock.

In testimony that I claim the foregoing as my invention I affix mysignature in presence of two witnesses.

FREDERICK N. GARDNER.

Witnesses:

EDWARD LARSON, tnonon DORMER.

